Risk perception of car drivers toward E-scooters and bicycles

The increasing adoption of electric scooters (ESs) presents opportunities and challenges for urban transportation systems. ESs face unique integration challenges in Japan owing to the lack of bicycle infrastructure and recent regulatory shifts. Consequently, understanding how surrounding car drivers perceive ES risks in the current road environment is crucial for improving road safety. This study employed a web-based questionnaire survey targeting car drivers who regularly encountered ESs at least once a week. We analyzed the perceived level of danger and the frequency of hazardous behaviors associated with ES riders and cyclists. The results indicate that drivers perceive ES-related behaviors as significantly more dangerous than bicycle-related behaviors, despite observing the former less frequently. Age, risk experience, usage experience, and road geometry have been found to influence the perceived level of danger of hazardous behaviors. Car drivers perceive traffic violations by cyclists and ES riders at high frequencies and danger levels. Compared to drivers unfamiliar with using ESs, those familiar with using ESs perceive behaviors related to operational instability from ES riders more frequently—a pattern not observed for bicycles. Infrastructure plays a critical role in reducing the perceived level of danger: dedicated lanes and arrow markings on shared lanes reduce the perceived danger for both modes. This study contributes to identifying factors influencing risk perception among surrounding car drivers in the early stages of the spread of new mobility, when adoption is not yet sufficient and actual user maneuver surveys are difficult to conduct efficiently. Combining the factors identified in this study with future objective evaluations leads to the development of effective countermeasures. • Car drivers perceive ES (E-scooter) hazardous behaviors less frequently but more dangerous than bicycles. • Drivers' risk perception toward ESs and bicycles are influenced by age, risk experience, use experience, and road geometry. • ES behaviors related to operational instability are reported more frequently by car drivers with ES experience. • Car drivers with experience of either ES use or d ES-related crash experience tend to underestimate the risks of ESs. • Arrow markings on shared lanes reduced the perceived danger of both bicycles and ESs.